Article
Engineering, Electrical & Electronic
Qiming He, Weibing Hao, Xuanze Zhou, Yu Li, Kai Zhou, Chen Chen, Wenhao Xiong, Guangzhong Jian, Guangwei Xu, Xiaolong Zhao, Xiaojun Wu, Junfa Zhu, Shibing Long
Summary: This work demonstrates vertical beta-Ga2O3 Schottky barrier diodes (SBDs) breaking through the power figure of merit of 1 GW/cm(2) without edge termination. The unreliable surface on the top of the drift region, which naturally formed in air, was removed by inductively coupled plasma etching. The repaired surface was exposed to ambient air for less than 10 minutes during the entire preparation process. Compared with the excessive air exposure samples, the leakage current was well suppressed for the Ni/beta-Ga2O3 SBDs fabricated on a clean surface. Moreover, the blocking voltage reaches a maximum value of 1720 V, and the forward/reverse characteristics of the diodes on the same wafer show good uniformity. These results pave the way for further improving the performance of beta-Ga2O3 devices and verify the potential of beta-Ga2O3 SBDs for power applications.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Chemistry, Physical
Jakub Kierdaszuk, Ewelina Rozbiega, Karolina Pietak, Sebastian Zlotnik, Aleksandra Przewloka, Aleksandra Krajewska, Wawrzyniec Kaszub, Maria Kaminska, Andrzej Wysmolek, Johannes Binder, Aneta Drabinska
Summary: The study demonstrates effective gating of graphene at low bias using four-layered graphene/gallium nitride (GaN) Schottky diodes and undoped GaN spacer, suggesting their potential for applications. The observed Raman G band position shift and splitting indicate turbostratic layer stacking and high potential gradient near the Schottky junction. Analysis based on electroreflectance measurements and a modified Richardson equation confirms graphene behavior as a capacitor at reverse bias on n-GaN separated by an undoped GaN spacer.
APPLIED SURFACE SCIENCE
(2021)
Article
Engineering, Electrical & Electronic
Yuxi Wei, Xiaosong Peng, Zhuolin Jiang, Tao Sun, Jie Wei, Kemeng Yang, Linyao Hao, Xiaorong Luo
Summary: In this study, a reverse conduction beta-phase gallium oxide (beta-Ga2O3) vertical FinFET with an integrated Fin diode (FD) is proposed to improve reverse conduction characteristics without affecting threshold voltage (V-th) and breakdown voltage (BV). Through TCAD simulation, the electrical characteristics of the device are studied and analyzed. The FD achieves MIS-like conduction/blocking characteristics through the Fin channel and an Ohmic contact anode, enhancing the device's reverse current capability.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Qiming He, Xuanze Zhou, Qiuyan Li, Weibing Hao, Qi Liu, Zhao Han, Kai Zhou, Chen Chen, Jinlan Peng, Guangwei Xu, Xiaolong Zhao, Xiaojun Wu, Shibing Long
Summary: Selective high-resistance zones were successfully achieved on beta-Ga2O3 wafers using a high-temperature oxygen annealing process. Polysilicon was employed as an annealing cap layer to prevent local carrier concentration changes during annealing. Additionally, a high-resistance anode edge termination of Schottky barrier diodes was demonstrated, leading to reduced leakage current and increased breakdown voltage.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Energy & Fuels
Vishwajeet Maurya, Julien Buckley, Daniel Alquier, Mohamed-Reda Irekti, Helge Haas, Matthew Charles, Marie-Anne Jaud, Veronique Sousa
Summary: We studied the temperature-dependent reverse characteristics (J(R)-V-R-T) of vertical GaN Schottky-barrier diodes with and without a fluorine-implanted edge termination (ET). Through temperature-dependent characterizations and technology computer-aided design modeling, we observed different levels of current in both forward and reverse biases for the ET and non-ET devices, indicating a change in the conduction mechanism for the observed leakages. We successfully fitted the measured J(R)-V-R-T characteristics of the non-edge-terminated device with the phonon-assisted tunneling model, while for the edge-terminated device, the reverse characteristics were modeled by considering the emission of trapped electrons and field caused by Poole-Frenkel emission at high temperature.
Review
Physics, Applied
Chao Lu, Xueqiang Ji, Zeng Liu, Xu Yan, Nianpeng Lu, Peigang Li, Weihua Tang
Summary: This review summarizes recent research progress on beta-Ga2O3-metal contacts, including related theories, measurements, fabrication processes, and control methods. These studies provide important insights for both theoretical understanding of the metal/semiconductor interface and the fabrication process for engineering applications of Ga2O3-based devices.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Yuxi Wei, Xiaorong Luo, Yuangang Wang, Juan Lu, Zhuolin Jiang, Jie Wei, Yuanjie Lv, Zhihong Feng
Summary: This study proposes an ultrafast reverse recovery beta-Ga2O3 Schottky barrier diode with improved breakdown voltage, featuring a compound termination design. The compound termination effectively reduces reverse leakage current, enhances reverse recovery and breakdown characteristics, showing great potential for high power and high-frequency applications.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Materials Science, Multidisciplinary
Byungsoo Kim, Duyoung Yang, Woonbae Sohn, Seungmin Lee, Hwan-Hee-Chan Choi, Taehoon Jang, Euijoon Yoon, Yongjo Park, Ho Won Jang
Summary: The use of compositionally graded α-(AlxGa1-x)2O-3 layers reduces threading dislocations and improves the crystalline quality of epitaxial α-Ga2O3 films. The strain relaxation and dislocation inclination in the graded α-(AlxGa1-x)2O-3 layers were confirmed through reciprocal space mapping and transmission electron microscopy studies. Dislocations annihilation in the graded α-(AlxGa1-x)2O-3 layers led to a significant reduction (64.9%) in the density of threading dislocations in α-Ga2O3 films compared to those grown directly on a sapphire substrate.
Article
Physics, Applied
Yaqiang Liao, Tao Chen, Jia Wang, Yuto Ando, Wentao Cai, Xu Yang, Hirotaka Watanabe, Jun Hirotani, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Kevin J. Chen, Hiroshi Amano
Summary: The vertical GaN-on-GaN nanowire Schottky barrier diodes (NWSBDs) fabricated using an optimized top-down approach exhibit suppressed reverse leakage current and enhanced breakdown voltage attributed to reduced electric field at the Schottky junction interface. The as-fabricated NWSBD demonstrates a low turn-on voltage, near-unity ideality factor, and a soft breakdown voltage comparable to p-n diodes with similar net doping concentration in the drift region.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Optics
Bo Peng, Lei Yuan, Hongpeng Zhang, Hongjuan Cheng, Shengnan Zhang, Yimen Zhang, Yuming Zhang, Renxu Jia
Summary: A Schottky barrier diode solar-blind photodetector was fabricated on a single crystal beta-Ga2O3, showcasing a high light to dark current ratio and fast response speed at 254 nm. The device exhibits self-powered action and linearly enhanced photocurrent with increasing illumination intensity. The photoresponse time varies under different bias conditions, suggesting a mechanism involving the release of trapped carriers under applied bias.
Article
Engineering, Electrical & Electronic
Ali Osman Tezcan, Serkan Eymur, Enis Tasci, Mustafa Emrullahoglu, Nihat Tugluoglu
Summary: The study utilized a BODIPY-based BOD-Z-EN compound as an interfacial organic layer in the fabrication of an Au/BOD-Z-EN/n-Si/In diode. Electrical parameters of the diode were investigated at different illumination intensities, showing variations in ideality factor, barrier height, and series resistance. The diode exhibited photovoltaic behavior with specific parameters under different light intensities, demonstrating its potential as a photosensor in optoelectronic applications.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Materials Science, Multidisciplinary
Min-Yeong Kim, Hee-Jae Lee, Dong-Wook Byun, Seung-Woo Jung, Myeong-Cheol Shin, Michael A. Schweitz, Sang-Mo Koo
Summary: This study analyzes the effects of annealing on the electrothermal properties of Gallium Oxide (Ga2O3) thin films. The results show that the annealed sample has high current performance with a slight temperature rise.
Article
Engineering, Electrical & Electronic
Ya-Xun Lin, Der-Sheng Chao, Jenq-Horng Liang, Yao-Luen Shen, Chih-Fang Huang, Steve Hall, Ivona Z. Mitrovic
Summary: This article introduces quasi-vertical Schottky Barrier Diodes (SBDs) fabricated on a GaN on Si substrate, which exhibit near ideal turn-on voltage and ideality factor (n = 1.02). The study shows that the diodes have an average turn-on voltage of 0.23 ± 0.005 V (at 1 A/cm2) and an on-resistance of 1.76 ± 0.11 mΩcm2, with a diode series resistance of 11Ω. Analysis of the current-voltage curve reveals a temperature-independent barrier height, while the capacitance-voltage method demonstrates a negative temperature coefficient. The dominant reverse current leakage mechanism in the fabricated diode is shown to be variable range hopping through dislocations, with a characteristic temperature, T0, of 2 × 1010 K.
SOLID-STATE ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Feng Zhou, Weizong Xu, Fangfang Ren, Dong Zhou, Dunjun Chen, Rong Zhang, Youdou Zheng, Tinggang Zhu, Hai Lu
Summary: A quasi-vertical GaN junction barrier Schottky diode on low-cost sapphire substrate was successfully demonstrated, exhibiting excellent performance attributes such as low reverse leakage, high breakdown voltage, and fast switching capability. Improved heat dissipation techniques enable the diode to achieve high current rectification levels, high power efficiency, and low case temperatures.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Liuan Li, Xiaobo Li, Taofei Pu, Shaoheng Cheng, Hongdong Li, Jin-Ping Ao
Summary: The vertical GaN Schottky barrier diode, fabricated as a temperature sensor using a thermally stable TiN anode, displays a zero-temperature coefficient bias point and a linear decrease in forward voltage with increasing temperature in the sub-threshold region. Additionally, the leakage current in the reversely biased region shows temperature-dependent behavior with a sensitivity of approximately 19.7 mA/K regardless of the bias. These results can be explained by the thermionic emission model.
IEEE SENSORS JOURNAL
(2021)
Article
Crystallography
Pradeep Desai, Bhagyashri Todankar, Ajinkya K. Ranade, Masaharu Kondo, Takehisa Dewa, Masaki Tanemura, Golap Kalita
Summary: A method for synthesizing MoS2 crystals on GaN using ATM precursor is reported, leading to the fabrication of heterojunction devices with excellent performance. X-ray photoelectron spectroscopy was used to explore the interface quality between MoS2 crystals and GaN wafer.
CRYSTAL RESEARCH AND TECHNOLOGY
(2021)
Article
Energy & Fuels
Kohei Kondo, Yusuke Watanabe, Junya Kuno, Yosuke Ishii, Shinji Kawasaki, Masashi Kato, Golap Kalita, Yoshiyuki Hattori, Oleksandr Mashkov, Mykhailo Sytnyk, Wolfgang Heiss
Summary: By investigating the photocatalytic properties of organic semiconductors and heterostructure effects, it was found that depositing Ni metal further enhanced the photoresponse current and improved the durability of the organic semiconductors. A flexible photocatalytic electrode for solar hydrogen generation was successfully prepared.
Article
Biochemical Research Methods
Annika Durve Gupta, Arvind Gupta, Almendra Reyes-Calderon, Victor Ishrayelu Merupo, Golap Kalita, Jose Herrera-Celis, Naresh Chandra, Ashutosh Sharma, Jose Tapia Ramirez, L. G. Arriaga, Goldie Oza
Summary: Metal sulfide nanoparticles were synthesized using Pseudomonas aeruginosa from textile effluent, showing optical, structural, and morphological characteristics. Analysis revealed functional groups on the bacteria surface aiding metal binding, with changes in protein concentration and banding pattern under heavy metal stress.
JOURNAL OF FLUORESCENCE
(2021)
Article
Chemistry, Multidisciplinary
Bhagyashri Todankar, Pradeep Desai, Ajinkya K. Ranade, Tharangattu N. Narayanan, Masaki Tanemura, Golap Kalita
Summary: In this study, the effective trifunctional electrocatalytic properties of nitrogen-doped graphitic carbon nanofibers on a binary metal substrate were demonstrated, showing potential for application in oxygen reduction, oxygen evolution, and hydrogen evolution reactions. This indicates the significance of incorporating metal particles in electrocatalysts to enhance their performance.
Article
Materials Science, Multidisciplinary
Golap Kalita, Balaram Paudel Jaisi, Masayoshi Umeno
Summary: In this study, a novel microwave-excited surface-wave plasma process was demonstrated to reduce insulating graphene oxide to highly conducting reduced graphene oxide on flexible substrates, as well as achieving reduction of freestanding graphene oxide paper.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Physics, Condensed Matter
Hisashi Sato, Yuya Ito, Golap Kalita, Yoshimi Watanabe
Summary: The crystallographic texture of pure Cu can be modified by shot peening, resulting in the formation of a {110} fiber texture. Moreover, using shot-peened specimens with {110} fiber texture improves the growth of high-quality graphene on their surfaces. Therefore, controlling the crystallographic texture by shot peening is of great importance for preparing high-quality graphene and other catalytic substrate surfaces.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Bhagyashri Todankar, Yazid Yaakob, Golap Kalita, Masaki Tanemura
Summary: Urea oxidation reaction (UOR) catalysts have been extensively studied due to their affordability, ease of storage and shipment, as well as their non-toxic and non-combustible characteristics. In this study, nitrogen doped carbon nanofibers (CNFs) grown on nichrome foil were investigated as a potential catalyst for urea fuel cells. The CNFs exhibited significant urea oxidation reaction in various molar concentrations of urea, making them a promising candidate for urea oxidation.
Article
Chemistry, Multidisciplinary
Venkata Krishna Rao Rama, Ajinkya K. Ranade, Pradeep Desai, Bhagyashri Todankar, Golap Kalita, Hiroo Suzuki, Masaki Tanemura, Yasuhiko Hayashi
Summary: We investigated the device properties of a nickel-gallium oxide Schottky junction with an interfacial hexagonal boron nitride layer. The addition of the hBN layer significantly enhanced the turn-on voltage for forward current and improved the photoresponsivity under deep ultraviolet light illumination. The hBN interfacial layer can serve as a barrier layer to control the turn-on voltage and optimize the device properties for deep-UV photosensor applications.
Article
Materials Science, Multidisciplinary
Faysal Selimoglu, Bahri Gur, Muhammed Emre Ayhan, Fatma Gur, Golap Kalita, Masaki Tanemura, Mehmet Hakki Alma
Summary: Procalcitonin(PCT) is a highly sensitive biomarker for severe inflammation and infection in the early detection of sepsis. The interaction between electrode material and attached material is important. A silver nanoparticle (AgNp) doped graphene-based sensitive PCT biosensor with low-cost, environmentally friendly materials is presented here. The biosensor exhibits reusability, adhesion of antibody-protein, and a detection limit of 0.55 ng/mL.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Balaram Paudel Jaisi, Rucheng Zhu, Golap Kalita, Masayoshi Umeno
Summary: The growth of carbon thin films on insulating substrates with nitrogen doping at various temperatures was investigated using microwave-excited surface wave plasma chemical vapor deposition technique. Partially graphitized carbon thin films were obtained at a low temperature of 150 degrees C on quartz substrates. The addition of nitrogen reduced the granular morphology and formed planar structures, revealing the significance of nitrogen incorporation in controlling the morphology of carbon films.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Review
Chemistry, Physical
Golap Kalita, Takashi Endo, Toshihiko Nishi
Summary: This paper reviews the synthesis methods of oxide-based solid-state electrolytes (SSEs), focusing on the low temperature synthesis of cubic-phase LLZO particles and the challenges in achieving high relative density with excellent ionic conductivity. The future prospects of applying these ultrafine particles in all-solid-state batteries are also discussed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
K. F. Chan, A. K. Ranade, P. Desai, M. A. Hazan, N. F. I. Azman, S. Shaharifin, G. Kalita, M. S. Mamat, M. Tanemura, Y. Yaakob
Summary: Carbon nanomaterials have significant applications in various fields, and green synthesis of these materials using low-cost and energy-efficient methods is of great interest. In this study, carbon nanotubes and graphitic carbon layers were synthesized using barbeque grease as the carbon precursor via chemical vapour deposition technique. The research aimed to explore novel and affordable carbon precursors for high-quality carbon nanomaterial production.
Article
Chemistry, Multidisciplinary
Gauravjyoti D. Kalita, Podma P. Sarmah, Golap Kalita, Pankaj Das
Summary: A facile ligand-assisted approach was used to synthesize bimetallic Au-Pd nanoparticles with a tunable core@shell structure. The Au-Pd materials exhibited superior performance in two important reactions, with the Pd-core-Au-shell structure showing higher activity compared to the Au-core-Pd-shell structure.
NANOSCALE ADVANCES
(2021)
Correction
Chemistry, Multidisciplinary
Pallavi Thakur, Jamsad Mannuthodikayil, Golap Kalita, Kalyaneswar Mandal, Tharangattu N. Narayanan
Summary: The study describes a method for in situ surface modification of materials by cytochrome C for active hydrogen evolution catalysis.
MATERIALS CHEMISTRY FRONTIERS
(2021)
